Lactococcosis is a disease encountered in a wide variety of fish species causing mortalities and having great economic impact on farmed fish. Lactococcus garvieae, a highly diverse species, is considered to be the causative agent of the disease and the first isolation of the bacterium in Greece was reported in 2003 from an epizooty in rainbow trout with a mortality varying 20-40% in different fish farms.
Lactococcus petauri sp. nov. was first described as a new species of the Lactococcus genus by Goodman et al. (2017). A bacterial strain, Lactococcus petauri sp. nov. 159469, isolated from a lesion of the chin of sugar glider (Petaurus breviceps) was described as a representative of the novel species. Phylogenetic and genotyping analysis revealed that this novel distinct species shares most of its genome with L. garvieae.
In our study we present results of a whole-genome analysis suggesting that one Lactococcus strain, LG_SAV_20, isolated in 2007 from rainbow trout suffering from lactococcosis belongs to the recently described novel species L. petauri sp. nov. Detection of genes associated with antimicrobial resistance indicated that the isolate possesses the multidrug transporter mdt(A) gene while using comparative analysis we identified several genes that might be related to bacterial pathogenesis. Characterization of genomic features of this strain contributes in better understanding its virulence potential and antibiotic resistance while comparative genome analysis reveals its phylogenetic relationship with other related Lactococcus isolates. Based on the data presented in our study, the availability of the genome sequence of L. petauri LG_SAV_20 strain will allow us to decipher the role of this novel species as an etiological agent of lactococcosis.
